Messages in this thread | | | Date | Tue, 11 Aug 2009 17:51:06 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v3] x86: clear incorrectly forced X86_FEATURE_LAHF_LM flag |
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On Tue, Aug 11, 2009 at 04:37:56PM +0200, Mikael Pettersson wrote: > Since the BIOS apparently wrote some MSR to get LAHF_LM incorrectly > reported by CPUID, would it be possible to also correct that MSR so > that applications that execute CPUID get the correct feature flags?
That's a good catch, actually. We have to turn off that bit in the cpuid leaf too if the CPU doesn't support the instructions so that cpuid info is consistent. LAHF/SAHF support in 64bit mode has to be cpuid-checked prior to using them so that info has to be correct.
@Kevin: willing to try a patch or two?
-- Regards/Gruss, Boris.
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